How does a three-way light bulb work?

A three-way bulb has two filaments in it. The next time one burns out, carefully open it (for example, wrap it in a towel and hit it lightly with a hammer) and you will see the two separate filaments.

For the lowest setting, one filament comes on (it might be a 50-watt filament). For the next setting, the second filament comes on (it might be a 100-watt filament). For the third setting, both come on, for (in our example) a total of 150 watts.

Look also at the end of the bulb's base -- you will be able to see how the lamp controls the two filaments.

Let there be fluorescent light! Fluorescent lights are found everywhere, but do you know how they work? Those white tubes are more efficient than incandescent bulbs and don't get as hot. Take our quiz to see how much you know about the science inside these fluorescent lamps.

While buying an all-in-one home theater (also known as home theater-in-a-box, or HTIAB) simplifies a lot of your decisions about components, there's still a lot to learn about home entertainment technology. Think you know the ins and outs of home theater systems?